Despite the onstage incident, the 18-year-old heartthrob later tweeted that Glendale was a "great show" and said he was getting better before Sunday's show at Las Vegas, a magazine reported.(Pic Courtesy: Getty Images)

Video from the concert shows the teen singer turning his back toward the audience during "Out of Town Girl," hunching over, puking and then running for the side of the stage.(Pic Courtesy: Getty Images)